MacDebug

Verified for macOS Tahoe 26.2

How to Fix Sidecar Black Screen in macOS Tahoe 26.2

Is your iPad showing a black screen or "Timed Out" when trying to use Sidecar?

TL;DR fix

Follow Fix 1: The UI & Graphics Optimization — full Terminal commands and step-by-step instructions below. Verified on macOS Tahoe 26.2.

Recommended Troubleshooting Tool

Before proceeding with manual fixes, we recommend using CleanMyMac X. Ideal for scanning disks for errors and clearing hidden system junk.

The Symptom

Sidecar connects, but the iPad remains dark, or the connection drops after only a few seconds.

The Fix

  1. Trust the Device

Plug your iPad into your Mac via USB. If a "Trust this computer?" prompt appears on the iPad, tap Trust. This often fixes the wireless handshake.

  1. Sign Out of iCloud

Sidecar requires both devices to be on the same Apple ID with Two-Factor Authentication. Try signing out and back in on the iPad.

  1. Restart the Sidecar Relay

Terminal:

killall sidecar-relay

Fix 3: The UI & Graphics Optimization

When the Mac's WindowManager is struggling to stream the desktop to the iPad.

Recommended Tool: CleanMyMac X

- Free Up RAM: Sidecar is memory-intensive. Flushing your RAM can provide the necessary buffer for a smooth video stream.

- Maintenance: Run the "Repair Disk Permissions" to ensure the Sidecar framework can access the necessary video encoders.

Tested and documented by the MacDebug team — about MacDebug. See also Photoshop & Adobe Apps Crashing on macOS Tahoe, Fix macOS "No AirPlay Found", or browse all guides on macdebug.